Rubber thread and method of making the same



Jan. 17, '1933.

B. CHISHOLM RUBBER THREAD AND METHOD OF MAKING THE SAME Filed Feb. 24, 1932 Patented Jan. 17, 1933 PATENT OFFICE LESTER B. GHISHOLM, O1 PROVIDENCE, RHODE'ISLAND RUBBER THREAD AND METHOD OF MAKING SAME Application filed February 24, 1932. Serial No. 594,948.

This invention relates to a rubber thread suitable for use in the manufacture of elastic webs or fabric and for other similar purposes.

It is the general object of my invention to provide a rubber thread of novel and improved construction and of lowered manufacturing cost.

It is a further and important object of my invention to provide a rubber thread by the 9 use of which injuries to elastic fabric caused by puncture or breakage of threads will be effectively localized.

My invention also consists'in the provision of a new and improved method of producing 5 a rubber thread by a drawing rather than an exuding operation. My invention further relates to certain combinations of parts and steps of procedure which will be hereinafter described and more particularly pointed out in the appended claims.

A preferred form of my invention, to= gether with illustrative apparatus for producing the same, is shown in thedrawing, in

5 which Fig. 1 is a diagrammatic view of apparatus by which my improved rubber thread may be produced;

Fig. 2 is a side view of a portion of the 9 compound textile thread on which the rubber thread is formed;

Fig. 3 is a sectional side elevation of a portion of the rubber thread as it leaves the coatin and vulcanizing tanks, and

Tig. 4 is an enlarged sectional side elevation of a portion of the finished rubber thread.

In the manufacture of my improved rubber thread, I first form a compound thread 0 or core by taking a textile thread 10 and winding it closely with a second textile thread 11. These threads 10 and 11 are commonly and preferably of cotton, and the thread 10 is lighter and weaker than the thread 11.

During the winding operation, the thread 10 is held under suflicient tension so that the thread 10 remains substantially straight,

.. while the thread 11 is wound in coils around the straight-thread 10.

This compound cotton thread T may be stored'in any convenient manner, as on a spool S, from which it is supplied to the coating mechanism shown in Fig. 1. This mechanism may comprise guide-rolls'14 and 15, draft rolls 17, drawing rolls 18 and 19, a winding roll 20, and successive tanks or receptacles 24 and 25.

The tank 24 contains a liquid rubber or latex solution and has an opening in the bottom covered by a die plate 30. This plate 30 is provided with a hole or opening of the correct size to permit a thread of the desired diameter to be drawn therethrough.

The tank 25 is filled with an acid or sulphur solution which will have a hardening or 5 vulcanizing effect on the thread. The lower end of the tank 25 is provided with an outlet having a packing member or gland 32 permitting the partially hardened or vulcanized thread to be drawn therethrough but substantially preventing escape of liquid from the tank 25.

In the carrying out of my invention, the

vrolls 17, 18 and 19 are positively driven in definite speed relations. The draft rolls 17 draw the combined thread or core T from the spool S over the guide-rolls 14 and 15 and down through the tank 24, the die plate 30,

the tank 25 and the packing member or gland As the cotton thread T is drawn through the rubber or latex solution in the tank 24, it becomes thoroughly coated and impregnated with rubber. The surplus rubber is removed from the thread by the die plate 30, so that 35 the thread leaves the tank 24 as a rubbercoated but soft and exceedingly sticky thread T of the desired exterior diameter.

. This thread enters directly into the solution in the tank 25 without touching anyexternal object. As the thread is drawn down through the tank 25, the acid or sulphur solution has a suflicient hardening or vulcanizing effect so that the exterior of the thread is no longer sticky as it is drawn out through the outlet packing member 32 by the draft rolls 17.

The thread at this time is in the condition indicated at T in Fig. 3, with the original compound cotton thread Tembedded in and surrounded by a coatingef rubber or latex. V

As the thread '1" leaves the tension roll 17, it

. passes loosely to two'or more pairs of drawton thread 10 is broken up into a series of I short separate pieces as indicated at 100 in the finished thread T shown in Fig. 4.

This thread T is then allowed to contract and is wound on the roll or is otherwise stored for use as desired.

Thebroken in Fig. 1 indicate that the various parts of the diagrammatic apparatus may be spaced apart at any required distances.

I ton thread 10 is It thus appears that thread is formed by taking a compound cotton thread or core T, impregnating and coating it with a liquid rubber or latex solution, sizing the coated thread passing the thread directly to a second acid or sulphur solution by which the surface of the thread is hardened or vulcanized, and

thereafter subjectin .the thread to a stretching operation by which the straight weak cotbroken up into short pieces, leaving the thread '1 as shown in Fig. 4, with the coiled thread 11 embedded in the rubber but with the straight thread 10 so broken up that it does not interfere with the elasticity of the thread T. a

M improved rubberthread T produced as above described, may then be used for any of the-purposes to which barerubber threads are commonly applied, or it may be coated with silk or other fibre in the wellown commercial manner. This novel rubber thread may be very easily and cheaply produced, and it possesses one very important the threa advantage over the ordinary ru ber thread when used in elastic fabrics.

Much. waste is caused in the manufacture of articles f'rorn lastic fabric by the fact that the elastic threads are frequently punctured or broken by the needle of the machine which is used in sewing "the garment. When a thread is thus punctured or broken, it contracts for a considerable distance, frequently one or two inches, and leaves a visible defeet in the cloth which ma cause the garment to be classed as a secon and sold at a reduced price.

en my used, either bare or covered, the. coiled cotton threadll localizes any break in a thread which may occur from needle puncture or otherwise. The only efiect of such breakage isto strai hten one or two adjacent coils-of 11. The rubber thread thus remains substantially in its original position and without complete separation, the thread the advantages thereof, I do my improved rubber by the die plate 30,

tion by which the surface improved rubber threads are aeeaeer 11 being so embedded in'the rubber substance that no substantial separation is. possible. Runs in the fabric are thus avoided.

In a modified form thread 11 may be omitted and the weak straight thread only may be drawn through the tanks and coated as described. This form of thread possesses certain but not all of the advantages of the previously described thread.

Having thus described my invention and not'wish to be limited to the details herein described, otherwise than as set forth in'the claims, but what I claim is 1. As an article of manufacture, a rubber thread comprising a compound textile core impregnated and covered with rubber, said core being formed of a straight and re1a-v .tively weak thread in short fragments in the finished product, and a winding thread disposed in helical coils around said straight core thread.

2. The method of making a rubber thread i which comprises takin a relatively weak core thread, drawing sai core thread through a rubber solution whereby said core thread is impregnated and coated with rubber, drawing said coated thread through a second soluof the rubber thread is rendered substantially non-adhesive, and thereafter breaking said core thread into short discontinuous fragments, whereb stretching of said rubber thread is facilitate 3. The method of making a rubber thread which comprises'forming a compound core thread by holding a relatively straight and winding a second thread in helical coils about said straight-thread, drawing said compound core thread through a rubber-solution whereby said core thread is impregnated and coated with rubber, drawing said coated thread through a through a second solution by whic the surface of the rubber thread is rendered substantially non-adhesive, and thereafter'breakmg said core thread into short discontinuous fragments whereby stretching of thread is facilitated.

4. The method of making a rubber thread which thread by holding a relatively weak thread straight and winding a second thread in helical coils about said straight thread, drawing said compound core thread through a rubber solutionwhereby said core thread is impregnated and coated with rubber, drawin said coated thread through a die plate an through a second solution by which the surface of the rubber thread is rendered substantially non-adhesive, and thereafter submitting said coated thread to a stretching operation by which the straight core thread is broken into short discontinuous fragments.

5. The method of making ,a rubber thread of my invention, the

discontinuous die late and weak thread A said rubber ing said which com rises forming a compound core thread by olding a relatively weak thread straight and windin a second thread in helical coils about sai strai ht thread, drawin said compound core t read through a ruhber solution whereb said core thread is impregnated and coated with rubber, drawing said coated thread through a die plate and through a second solution by which the surface of the rubber thread is rendered sub stantially non-adhesive, and thereafter passcoated thread through succewive drawing rolls by which the straight pairs of short discontinucore thread is broken into ous fragments. v

In testimony whereof I have hereunto affixed my signature.

LESTER B. CHISHOLM. 

